Honestly, no.
MP's should live in their constituency, but clearly Parliament demands they spend considerable time in London too.
I can see the business need to have a "second home", if you work 100 hours per week, quite a bit of that in London - working sometimes late into the night. It's common-sense practical.
The expense rules should ensure that this is not exploited as a perk.

How come Kelvin Hopkins can live in Luton (a 45 minute commute from Zone 1) and doesn't need a second home, but David Cameron can't get the train from Oxford?

See, when some of them manage it quite adequately, then it's surely -- by definition -- a perk for the others?

As I say, I understand it if your constituency is Newcastle or Cornwall. But Oxford? Does Cameron work that much harder than every other commuter who makes the journey from Oxford every day? So much harder that the rest of them need to subsidise him to the tune of One London House?

Bollocks does he.

As I've said elsewhere though, I'm sure the tories will fire a bunch of teachers and close some hospital wards as soon as they take office. That'll save the treasury far more than they've helped themselves to. So much more, in fact, that they might even have enough left over to reduce taxes for high earners like themselves.